Dry shampoo using chitin powder

ABSTRACT

A dry shampoo containing chitin powder is disclosed.

This invention relates to dry shampoos which are applied to the hair inpowdered form, and then removed from the hair by brushing, therebyremoving from the hair oil or sebum which becomes attached to the drypowder. More specifically, this invention relates to dry shampoos inwhich the active oil removing powder is chitin.

Dry powder shampoos are known, but have not been particularly popularlargely because they are rather inefficient in removing sebum from thehair. Currently available dry powder shampoos consist of an activepowder suspended in a carrier. When used, the powder is sprayed onto thehair, the carrier evaporates, the sebum from the hair is absorbed by thepowder, and the powder is removed by brushing the hair. By this means,the hair is cleaned. Usually, these dry powder shampoos use starch asthe active powder, and unfortunately starch tends to remain attached tothe hair and is not readily removed after treatment. This is illustratedin Example II. While dry shampoos could be formulated with other powderssuch as activated carbon and alumina, such shampoos would not bedesirable because the other powders are not biodegradable, and aredifficult to remove from the hair. Alumina, for example, has been testedand found to be efficacious in removing sebum. However, it is unsuitablefor use in a dry powder shampoo because it leaves behind a residue whichcauses the hair to feel gritty. Similarly, activated carbon leaves aresidue on the hair which gives it a dark sooty appearance. Otherpowders such as pulverized clay, silica, and talc could be used in dryshampoo, but again these powders have the disadvantage that they are notbiodegradable and tend to be difficult to remove from hair.

A truly efficacious dry powder shampoo would be useful in situationswhere the use of a water-base product is inconvenient or impossible. Forexample, bedridden patients might very well find it impossible to washtheir hair with a water-based shampoo but could use a dry powdershampoo. In addition, people must wash and dry their hair in a hurrywould welcome the convenience of a dry shampoo. Therefore, it would bedesirable to have a dry powder shampoo and which was truly effective inremoving oil from the hair, which did not at the same time present thehazards and the inconveniences of powders such as alumina, activatedcarbon, clay, silica and talc.

It is, therefore, an object of the present invention to provide anefficient, non-toxic biodegradable dry powder shampoo.

Accordingly, the present invention provides dry powder shampooformulations based on chitin powder which is an ideal active ingredientfor such use. Chitin itself, is a naturally occurring form ofpoly-N-acetyl glucosamine which may be isolated from several sources,expecially the exoskeleton of crustacea, such as shrimp. Chitin isreadily broken down by enzymes found in body fluids, and thus, willpresent no hazard if it should accidently be swallowed, come in contactwith an abraided area of the skin or get into the user's eyes. Chitinwhich does come into contact with body fluids, will be readily brokendown into soluble, nontoxic materials. From the point of view of safety,therefore, chitin is desirable as an active ingredient in dry powdershampoos.

The size of the chitin particles making up the powder is not critical aslong as it is appropriate for spraying. In other words, any particlewhich is suitable for spraying has the properties necessary for use in aspray shampoo. Generally, particles of about 10 to 75 microns in sizeare readily sprayable. For a discussion of characteristics of sprayablepowders, see Cosmetics Science and Technology by Edward Sagarin,Interscience Publishers (1957) pp. 834-5, which is hereby incorporatedby reference. It should be noted that chitin powder is ideal forspraying because the powder particles are well shaped, are insoluble incarrier fluids, and are not subject to agglomerative sedimentation.

Powdered chitin has a large surface area and is highly porous andtherefore, readily takes up oily substances such as sebum, either byadsorption on the surface or by absorption into the pores. Hereinafter,the term absorption will be used to denote this take up of oilymaterials without regard to whether the actual process occurring isadsorption or absorption. In tests of the ability of dry powder shampoocompositions to remove synthetic sebum (prepared as shown in Example I)from hair tresses, chitin powder has been found to be much more activethan starch powder. The tests were conducted by coating the hair withsynthetic sebum and spraying the hair with the powder suspended in ethylalcohol. The hair is then dried and brushed to remove the powder. Themethod and results are more fully described in Example II.

In formulating a dry powder shampoo, it is desirable that the activepowder ingredients be suspended in a volatile liquid carrier to thatthis suspension may be sprayed onto the hair. This technique isdesirable for two reasons. First, the presence of the volatile liquidallows the dry powder to penetrate closer to the scalp because it iscarried there by the liquid, and second, the presence of the volatileliquid controls the undesirable tendency of the active powder to form acloud of dust instead of remaining on the user's hair. In addition,certain volatile fluids act to dissolve the sebum from the hair andcarry it into the active powder prior to the evaporation of the volatileliquid. The quantity of the carrier should be sufficient to accomplishits objectives but not so great as to excessively wet the hair. Theratio of carrier to chitin powder may vary from about 5 to 1 to 1:1 byweight.

Many organic substances or mixtures thereof, may serve as the volatileliquid. The primary considerations in the selection of such a liquid arethe relative toxicity of the vapor and the irritancy of the liquid tothe user's skin. Other important considerations in selecting a volatileliquid are the flammability of such liquid and the exact degree ofvolatility. While obviously, the invention is operative even if a highlyflammable substance is used as the volatile liquid, it is preferableeither to avoid the use of highly flammable liquids, or to use them inconjunction with non-flammable liquids.

Liquids with boiling points ranging from about -30° to about 82° C. maybe used as the volatile liquid in conjunction with the chitin powder.Compounds with suitable properties include esters such as ethyl acetateand methyl acetate; ketones such as methyl ethyl ketone and acetone;hydrocarbons, such as the straight chained alkanes, butanes, pentane andhexane; cyclic hydrocarbons such as cyclopropane, cyclobutane,cyclopentane, and cyclohexane; branched chain hydrocarbons such as2,2-dimethyl propane, the methyl pentanes, the dimethyl pentanes and thedimethyl butanes; alcohols, such as ethyl alcohol and iso-propylalcohol, ethers, such as dimethyl ether, diethyl ether, diisopropylether, the methyl ethers of ethyl, isopropyl, propyl, n-butyl, t-butyland isobutyl alcohols, and the ethyl ethers of n-propyl, isopropyl,isobutyl, t-butyl and 2-butyl alcohols; and fluorine containing alkylhalides, such as dichloro-difluoromethane, 1-chloro, 1,1-difluoroethane,octofluorocyclobutane, 1,2-dichloro-1,1,2,2-tetrofluoromethane,dichloro-fluoromethane and fluoro-trichloromethane.

As noted above, the volatile liquid may consist of either a single purematerial or a combination of materials. It is preferred that liquids ateither extreme of the boiling point range not be used above, but ratheras part of a mixture of substances acting as a carrier. For example,extremely volatile liquids, such as dichloro difluoromethane may bemixed with a relatively non-volatile liquid such as ethanol. As notedabove, in selecting a carrier substance, consideration should be givento the fire hazard which the substance might present. Thus, the ethersand hydrocarbons are rather hazardous materials, while the alkylfluorides present no fire hazard. It is preferred that the volatileliquid contain a non-flammable fluorocarbon or mixture thereof if thehighly flammable hydrocarbons or ethers are used.

The dry powder shampoo may be applied either from aerosol cans, or froma hand operated spray device. If the dry powder shampoo is sprayed froman aerosol can, a propellant substance must be used. The choice ofpropellant material is not critical and any nontoxic substance whichdevelops the requisite pressure may be used to perform the essentiallymechanical function of driving the volatile liquid and the powder out ofthe aerosol container. All propellants which are commonly used inaerosol cans are, of course, suitable for use in this application. Lowboiling substances suitable for use as the volatile liquid may alsoserve as a propellant.

The following examples are provided for illustrative purposes only andmay include particular features of the invention. However, the examplesshould not be construed as limiting the invention. Many variations ofwhich are possible without departing from the spirit or scope thereof.

EXAMPLE I Preparation of Synthetic Sebum

The following ingredients were mixed and warmed to approximately 30° C.to form a clear solution.

    ______________________________________                                        Squalene                 5       parts                                        Olive Oil                32                                                   Paraffin Oil, Saybolt Visc 335/350                                                                     20                                                   Oleic Acid               14                                                   Linoleic Acid            6                                                    Lauric Acid              1                                                    Myristic Acid            2                                                    Palmitic Acid            4                                                    Stearic Acid, USP        2                                                    Spermwax                 6                                                    Coconut Oil              4                                                    Mixed Sterols            4                                                                             100                                                  ______________________________________                                    

Upon cooling to room temperature, a slight haze develops.

This formula is a modification of one given by G. Barnett and D. H.Powers in the Toilet Goods Association December, 1955, p. 24.

EXAMPLE II The Effectiveness of Various Dry Powder Shampoos

To one end of a 3 g. hair tress was applied approximately 0.24 g. (8% ofthe hair weight) artificial sebum prepared according to Example I. Thetress was given 175 brush strokes to distribute the sebum evenly, andthen weighed to determine the weight of sebum actually deposited. Amixture of 2 grams of ethyl alcohol and 0.5 g. of the powder to betested were sprayed onto the free hanging tress. The alcohol was allowedto evaporate, and the tress was again weighed to determine the weight ofpowder deposited. The tress was then given 60 brush strokes to removethe powder, and dried in a vacuum oven at 70° C. overnight. A finalweighing was then made to determine the amount of sebum removed by thepowder. A sample of synthetic sebum lost only about 2% of the weightunder the overnight drying conditions. Two separate runs were done withchitin powder, and four were done with starch. The results for eachpowder were averaged and are shown in the table below.

                  TABLE                                                           ______________________________________                                        Sebum Removal by Various Powders                                              Wt. of hair                                                                             %                 Wt. Powder                                                                              % Sebum                                 at 0% RH  Sebum.sup.1                                                                            Powder   applied g.                                                                              removed                                 ______________________________________                                        3.068     8.2      Chitin.sup.2                                                                           0.19        38                                    3.090     8.1      Starch.sup.3                                                                           0.19      -15.sup.5                               3.132     8.0      None.sup.4                                                                             0.011.sup.6                                                                             0.5                                     ______________________________________                                         .sup.1 Synthetic sebum prepared as shown in Example I                         .sup.2 -325 mesh                                                              .sup.3 -325 mesh                                                              .sup.4 2.5 grams of alcohol containing no powder were sprayed on the hair     Subsequently this sample was treated in the normal manner.                    .sup.5 The negative number indicates that the sample of hair gained weigh     in the test. This gain in weight results from starch adhering to the hair     .sup.6 Weight gained by tress after 2.5 g alcohol sprayed on and allowed      to evaporate.                                                            

We claim:
 1. A method of cleaning hair which comprises: spraying ontosaid hair a sprayable powder chitin being suspended in a non-toxicvolatile liquid carrier having a boiling point between about -30° and82° C., allowing said liquid carrier to evaporate, and removing theresidual powder from the hair.
 2. The method of claim 1 wherein thecarrier is a low molecular weight volatile alcohol.
 3. The method ofclaim 1 wherein the carrier is ethanol.
 4. The method of claim 1 whereinthe carrier comprises about 1 to 5 parts by weight per part of chitin.5. The method of claim 1 wherein the carrier is a low molecular weighthydrocarbon.